JP6263345B2 - Combustion abatement equipment - Google Patents

Description

  The present invention relates to a combustion abatement apparatus, and more specifically, a component having a combustion explosion risk or a toxicity risk contained in exhaust gas exhausted from a semiconductor manufacturing process for manufacturing an electronic component such as a semiconductor or liquid crystal, and an environmental impact. The present invention relates to a combustion abatement apparatus that removes harmful components such as large components in a combustion flame.

  Gases used in the manufacture of electronic components, as well as gases used in various industrial and medical fields, include gases with a risk of combustion explosion and toxicity, and gases with a large environmental impact. Since substances that react or decompose during use of various gases may have a risk of combustion explosion and toxicity, the exhaust gas exhausted from the process using these gases It is necessary to carry out detoxification treatment of various harmful components before releasing them into the atmosphere. As a means for removing harmful components in exhaust gas, conventionally, exhaust gas is introduced into a combustion flame and reacted or decomposed at a high temperature to remove the harmful components. In recent years, when exhaust gas is introduced into a combustion flame to remove harmful components, attention has been paid to a method in which the combustion flame is ejected in the tangential direction of the inner peripheral surface of the combustion cylinder to form a tubular flame (for example, Patent Documents 1 and 2).

Japanese Patent No. 3358527 Japanese Patent No. 4292926

  However, since the exhaust gas exhausted from the semiconductor manufacturing process is often sucked and extracted from the equipment by a vacuum pump, inert gas such as nitrogen gas used for the shaft seal of the vacuum pump is mixed in the exhaust gas. Further, depending on the harmful components, the exhaust gas is often diluted with an inert gas in order to ensure the safety of handling and the piping path. For this reason, the concentration of harmful components in the exhaust gas introduced into the combustion flame is not only diluted to a low level by being diluted with inert gas, but also because the total amount of gas for harmful components is large, Sex was sometimes lost. Further, depending on the type of harmful component, oxygen for reacting with the harmful component may be required in addition to oxygen for forming the flame.

  Therefore, the present invention provides a combustion abatement apparatus that can efficiently remove harmful components in exhaust gas diluted with an inert gas and can also effectively supply oxygen for reacting with the harmful components. The purpose is to do.

To achieve the above object, a combustion abatement apparatus of the present invention, the combustion scrubber for abatement treatment in the combustion flame of the toxic substances contained in exhaust gas, and the exhaust gas inlet pipe of inner diameter D0, the exhaust gas inlet A first processing cylinder having an inner diameter D1 provided on the downstream side of the pipe, a second processing cylinder having an inner diameter D2 provided on the downstream side of the first processing cylinder, and a downstream side of the second processing cylinder . A third processing cylinder having an inner diameter of D3, and the first processing cylinder includes a flame ejection hole having a circumferential width W1 for ejecting a combustion flame in a tangential direction from a peripheral wall of the first processing cylinder, The second processing cylinder includes an oxygen-containing gas ejection hole having a circumferential width W2 for ejecting the oxygen-containing gas from the peripheral wall of the second processing cylinder in a tangential direction, the inner diameter D1 is larger than D0 + 2W1, and the inner diameter D2 is D1 + 2W2. It is characterized by being set larger .

Furthermore, in the combustion abatement apparatus of the present invention, the third processing cylinder is formed in a double structure of an inner cylinder having an inner diameter D3 and an outer cylinder covering the outer periphery of the inner cylinder, While having an air introduction part for introducing air into an air introduction chamber formed between the outer cylinder and the inner cylinder, the inner cylinder has a large number of jets of air introduced into the air introduction chamber into the inner cylinder Air jet holes, and the inner diameter D3 is set to be equal to or larger than the inner diameter D2.

The exhaust gas introduction pipe has an axis that coincides with the axis of the first processing cylinder, and the downstream opening end of the exhaust gas introduction pipe is located at the same position or flame as the upstream end of the flame ejection hole in the first processing cylinder. It is characterized by projecting downstream from the upstream end of the ejection hole.

  Furthermore, between the first processing cylinder and the second processing cylinder, there is an axis that coincides with the axis of the first processing cylinder and the second processing cylinder, and the outer diameter is smaller than the inner diameter of the second processing cylinder. A cylindrical combustion gas introduction cylinder is provided, and the downstream opening end of the combustion gas introduction cylinder is located at the same position as the upstream end of the oxygen-containing gas ejection hole in the second processing cylinder or upstream of the oxygen-containing gas ejection hole It is characterized by protruding downstream from the end.

  In addition, the exhaust gas introduced into the combustion abatement apparatus is characterized by being diluted with an inert gas in order to reduce the concentration of harmful components.

  According to the combustion abatement apparatus of the present invention, the second processing cylinder having an inner diameter larger than the inner diameter of the first processing cylinder is provided on the downstream side in the gas flow direction of the first processing cylinder, and the oxygen-containing gas is supplied from the second processing cylinder. As a result, the oxygen-containing gas can be introduced without disturbing the tubular flame formed by the first treatment cylinder. Thereby, the harmful component can be reliably heated by the tubular flame, and oxygen necessary for the reaction can be supplied without disturbing the tubular flame. Therefore, it is possible to efficiently remove harmful components in the exhaust gas diluted with an inert gas that does not contribute to combustion.

  In addition, by providing a third processing cylinder formed of an inner cylinder having an air ejection hole and an outer cylinder having an air introduction portion on the downstream side of the second processing cylinder, solid substances can be removed by detoxification of harmful components. Even when (powder) is generated, solid matter with reduced temperature can be prevented from adhering and accumulating in the device, stable detoxification treatment can be continued, and combustion detoxification can be performed by the introduced air The temperature of the processing gas exhausted from the apparatus can be lowered. Furthermore, stabilization of the tubular flame can be achieved by providing the exhaust gas introduction cylinder and the combustion gas introduction cylinder.

It is a cross-sectional front view which shows one example of a combustion removal apparatus of this invention. It is explanatory drawing which shows the state of the flame ejection hole of a 1st process cylinder, and the oxygen-containing gas ejection hole of a 2nd process cylinder. It is a figure which shows the combustion characteristic in Experimental example 1. FIG. It is explanatory drawing of the experimental apparatus used in Experimental example 2. FIG. It is a figure which shows the combustion characteristic in Experimental example 2. It is a figure which shows the difference between nitrogen and air in Experimental Example 2. It is a figure which shows the combustion characteristic in Experimental example 3. Is a diagram showing the decomposition performance of NF ₃ in Experimental Example 3.

  The combustion abatement apparatus shown in the present embodiment is an apparatus in which a first processing cylinder 11, a second processing cylinder 21, and a third processing cylinder 31 are connected in order from the upstream side of the exhaust gas introduction pipe 10 in the gas flow direction. Thus, for example, exhaust gas obtained by diluting harmful components exhausted from the semiconductor manufacturing process with an inert gas is introduced from the exhaust gas introduction pipe 10.

  The first processing cylinder 11 is formed in a flat cylindrical shape, and the ejection direction B with respect to the inner peripheral surface A of the processing cylinder is set to the tangential direction of the inner peripheral surface A of the processing cylinder as shown in FIG. A plurality of flame ejection holes 12 having a circumferential width W1 and a length H1 are provided. The inner diameter D1 of the first processing cylinder 11 is set to be larger than the inner diameter D0 of the exhaust gas introduction pipe 10 (D0 <D1). Usually, the relationship of D0, D1, and W1 is set so that D1> D0 + 2W1. The Further, the length L1 of the first processing cylinder 11 is set to be 1.5 to 2 times the length H1 of the flame ejection hole 12. Furthermore, the circumferential width W1 of the flame ejection hole 12 is set such that the flow velocity of the flame ejected from the flame ejection hole 12 becomes a desired flow velocity with respect to the length H1, and is usually long in the gas flow direction. It is formed in a slit shape.

  The exhaust gas introduction part for introducing exhaust gas into the first processing cylinder 11 has an axial line that coincides with the axial line of the first processing cylinder 11 and has an outer diameter d1 that is smaller than the inner diameter D1 of the first processing cylinder 11. An introduction cylinder 13 is provided, and the downstream opening end 13 a of the exhaust gas introduction cylinder 13 protrudes to the same position as the upstream end 12 a of the flame ejection hole 12 in the first processing cylinder 11.

  The second processing cylinder 21 is formed in a flat cylindrical shape similar to that of the first processing cylinder 11, and the ejection direction B with respect to the inner peripheral surface A of the processing cylinder is formed on the peripheral wall as shown in FIG. A plurality of oxygen-containing gas ejection holes 22 that are set in the same direction as the ejection direction of the holes 12 and tangential to the inner peripheral surface A of the processing cylinder, have a circumferential width W2 and a length H2 are provided. The inner diameter D2 of the second processing cylinder 21 is set larger than the inner diameter D1 of the first processing cylinder 11 (D1 <D2), and normally, the relationship of D0, D1, and W2 is set so that D2> D1 + 2W2. Is done. Further, the length L2 of the second processing cylinder 21 is set to be 1.5 to 2 times the length H1 of the flame ejection hole 12. Further, the circumferential width W2 of the oxygen-containing gas ejection hole 22 is set so that the flow rate of the oxygen-containing gas ejected from the oxygen-containing gas ejection hole 22 becomes a desired flow rate with respect to the length H2, and normally , Formed into a slit shape long in the gas flow direction.

  Between the 1st processing cylinder 11 and the 2nd processing cylinder 21, it has an axis line which coincides with the axis line of the 1st processing cylinder 11 and the 2nd processing cylinder 21, and an outside diameter smaller than inner diameter D2 of the 2nd processing cylinder 21 A cylindrical combustion gas introduction cylinder 23 having d 2 is provided, and the downstream opening end 23 a of the combustion gas introduction cylinder 23 is the same as the upstream end 22 a of the oxygen-containing gas ejection hole 22 in the second processing cylinder 21. Projects to the position.

  In this way, the flame ejected from the flame ejection hole 12 of the first processing cylinder 11 is a laminar tubular flame in which the periphery of the exhaust gas introduced into the first processing cylinder 11 from the exhaust gas introduction pipe 10 is spirally wrapped. By forming, harmful components contained in the exhaust gas can be effectively heated. Then, the oxygen-containing gas ejected from the oxygen-containing gas ejection hole 22 of the second processing cylinder 21 having an inner diameter larger than the inner diameter of the first processing cylinder 11 flows into the second processing cylinder 21 from the first processing cylinder 11. Since the outer periphery of the tube is spirally circulated, oxygen in the oxygen-containing gas can be introduced into the exhaust gas flowing through the tubular flame without disturbing the combustion state of the tubular flame, and heated to a high temperature. It can react harmful oxygen and oxygen.

  Therefore, harmful components contained in the exhaust gas diluted with an inert gas that does not contribute to combustion at all can be efficiently thermally decomposed by the tubular flame formed by the first treatment cylinder 11 and detoxified. Even when the amount of harmful components is large, the harmful components can be efficiently detoxified by oxidizing and burning them with oxygen in the oxygen-containing gas introduced from the second processing cylinder 21. Even if solids are generated in the detoxification process, the oxygen-containing gas from the oxygen-containing gas ejection hole 22 flows along the inner peripheral surface of the second process cylinder 21, Solid matter can be prevented from adhering to the peripheral surface.

  Further, the downstream opening end 13a of the exhaust gas introduction cylinder 13 is protruded into the first processing cylinder 11, thereby stabilizing the flow of the introduced exhaust gas and preventing the exhaust gas introduction cylinder 13 from spreading into the first processing cylinder 11. Thus, the tubular flame can be more reliably formed in the first processing cylinder 11. Similarly, by providing a combustion gas introducing cylinder 23 with a downstream opening end 23a protruding into the second processing cylinder 21 between the first processing cylinder 11 and the second processing cylinder 21, a tubular flame is produced. The oxygen-containing gas introduced into the outer periphery can be made to flow along the outer periphery of the tubular flame, and the disturbance of the tubular flame flowing into the second processing cylinder 21 can be suppressed.

  That is, when the amount of combustible harmful components contained in the exhaust gas is small and the exhaust gas is mainly composed of inert gas, the amount of gas that does not contribute to combustion becomes excessive in the first processing cylinder 11 and the second processing cylinder 21. On the other hand, when the amount of combustible harmful components in the exhaust gas increases, the oxygen amount in the first processing cylinder 11 and the second processing cylinder 21 becomes insufficient, but the inner diameter D1 of the first processing cylinder 11 and the second processing. The inner diameter D2 of the cylinder 21 and the states of the exhaust gas introduction cylinder 13 and the combustion gas introduction cylinder 23 are appropriately set according to conditions such as the flow rate of exhaust gas and the concentration range of harmful components, particularly the concentration range of combustible components. Thus, it is possible to effectively remove the harmful components while suppressing the disturbance of the tubular flame.

  The third processing cylinder 31 has a double structure of a cylindrical inner cylinder 32 that is longer in the axial direction than the first processing cylinder 11 and the second processing cylinder 21 and an outer cylinder 33 that covers the outer periphery of the inner cylinder 32. An air introduction chamber 34 is formed between the inner cylinder 32 and the outer cylinder 33. An air introduction portion 35 for introducing air into the air introduction chamber 34 is provided on the peripheral wall of the outer cylinder 33, and the air introduced into the air introduction chamber 34 is supplied to the inner cylinder 32 of the inner cylinder 32. A large number of air ejection holes 36 that are ejected from the entire peripheral wall into the inner cylinder 32 are formed.

  The inner diameter D3 of the inner cylinder 32 is set to be equal to or larger (D2 ≦ D3) than the inner diameter D2 of the second processing cylinder 21, and usually D3 is 1.1 to 1.5 times as large as D2. Is set as follows. Further, the overall length L3 of the third processing cylinder 31 is set sufficiently long with respect to the inner diameter D3, and oxygen necessary for combustion and thermal decomposition is introduced into the combustion flame on the upstream side in the gas flow direction. In addition to promoting combustion and thermal decomposition, the downstream side is set to a length that allows the temperature of the gas flowing in the inner cylinder 32 to be appropriately cooled by mixing with the air ejected from the air introduction portion 35.

  In this manner, air is ejected from the air ejection hole 36 provided over the entire inner cylinder 32 toward the inside of the inner cylinder 32 at an appropriate flow rate and flow rate, thereby generating solids in the detoxification process of harmful components. Even in such a case, it is possible to suppress the solid matter from adhering to the inner peripheral surface of the inner cylinder 32, and the processing gas containing the solid matter can be smoothly led out of the apparatus. The change of the operation state due to the adhesion of the water will not occur.

  The exhaust gas introduction cylinder and the combustion gas introduction cylinder may be omitted, and the exhaust gas introduction cylinder may be formed by inserting the tip of the exhaust gas introduction pipe into the first processing cylinder to form the exhaust gas introduction cylinder. May be attached or formed integrally with each combustion chamber. In addition, the inner cylinder of the third treatment cylinder can be formed of a cylindrical material made of an appropriate material such as a metal porous plate or a net-like plate, or a multistage inner cylinder, and the size and number of air ejection holes, Arrangement is arbitrary, and a round hole, a square hole, a slit, etc. can be suitably selected also for the shape of an air ejection hole. Moreover, the magnitude | size of an air ejection hole etc. may differ in the upstream part and downstream part of an inner cylinder.

Experimental example 1
The inner diameter D0 of the exhaust gas introduction pipe is 80 mm, the inner diameter D1 of the first processing cylinder is 133.8 mm, the inner diameter D2 of the second processing cylinder is 133.8 mm (D2-D1 = 0 mm, D1: D2 = 1: 1) and 159. Combustion experiments were conducted using two types of devices set at 2 mm (D2-D1 = 12.7 mm, D1: D2 = 1: about 1.1). The length L1 of the first processing cylinder was 60 mm, and the flame ejection holes were provided with four slits with H1 of 30 mm and W1 of 4 mm at 90 ° intervals. The exhaust gas introducing cylinder was not provided, and the distance between the upstream edge of the slit and the upstream end surface of the first processing cylinder was set to 0 mm. From this flame ejection hole, propane gas and air premixed in a combustion state were evenly distributed and ejected. The length L2 of the second processing cylinder was 60 mm, and the oxygen-containing gas ejection holes were provided with four slits with H2 of 30 mm and W2 of 4 mm at intervals of 90 degrees. The distance between the upstream edge of the slit and the upstream end surface of the second processing cylinder was 0 mm. From this oxygen-containing gas ejection hole 22, 500 liters of air per minute was evenly distributed and ejected.

  Introducing 400 liters of nitrogen per minute from the exhaust gas introduction pipe, and maintaining a constant flow rate of propane gas between 8 and 25 liters per minute from the flame outlet, changing the amount of air to make a tubular flame The combustion state of was observed. The result is shown in FIG. From this result, it can be seen that by making the inner diameter D2 of the second processing cylinder larger than the inner diameter D1 of the first processing cylinder, the width of the air ratio that can form the tubular flame necessary for the processing becomes wider.

Further, as a gas introduced from the exhaust gas introduction pipe, a gas obtained by mixing 4 liters of silane (SiH ₄ ) per minute and 400 liters of nitrogen per minute is used in place of the nitrogen, and is generated by a detoxification reaction. The state in which silicon oxide (SiO ₂ ) adheres to the inner peripheral surface of the second processing cylinder was compared. As a result, when the inner diameter D2 of the second processing cylinder is 133.8 mm, 5 g adhered per hour, whereas the adhesion amount when the inner diameter D2 of the second processing cylinder is expanded to 159.2 mm is Less than 0.1 g per hour.

Experimental example 2
A combustion experiment was performed in which the relationship between the upstream end of the flame ejection hole of the first treatment cylinder and the downstream opening end of the exhaust gas introduction cylinder was changed. As shown in FIG. 4, the inner diameter D0 of the exhaust gas introduction pipe 10 is 43 mm, the inner diameter D1 of the first processing cylinder 11 is 56 mm, the length L1 is 50 mm, and the flame ejection holes 12 have H1 of 25 mm and W1 of 2 mm. Slits were provided at four positions at intervals of 90 degrees. From this flame ejection hole 12, propane gas and air previously mixed and burned were distributed evenly and ejected. The distance X between the upstream edge 12a of the slit and the downstream opening end 13a of the exhaust gas introducing cylinder 13 is based on the upstream end of the flame ejection hole (X = 0 mm), the downstream direction is positive, and the upstream direction is negative. The downstream opening end of the exhaust gas introduction cylinder was set to −5 mm (state shown in FIG. 4), 0 mm, and +5 mm with respect to the upstream edge 12a of the slit. Since the combustion state in the first processing cylinder only has to be observed, the second processing cylinder is omitted, and a protective cylinder 41 formed in the same manner as the third processing cylinder is disposed on the downstream side of the first processing cylinder. .

  While introducing 200 liters of nitrogen per minute from the exhaust gas introduction pipe at a constant flow rate, and maintaining a constant flow rate of propane gas between 2 and 10 liters per minute from the flame outlet, a tubular flame is produced by changing the amount of air. The combustion state of was observed. The result is shown in FIG. From this result, it is possible to widen the width of the air ratio that can form a tubular flame necessary for processing by setting the downstream opening end of the exhaust gas introduction cylinder to 0 mm and +5 mm, compared to the setting of -5 mm. Recognize.

  FIG. 6 shows the combustion state when 200 liters of air is introduced per minute instead of nitrogen from the exhaust gas introduction pipe when the downstream opening end of the exhaust gas introduction cylinder is set to −5 mm. From this result, it can be seen that the combustion range is narrower in the case of nitrogen that does not contribute to combustion compared to air containing oxygen. Therefore, when processing the exhaust gas diluted with the inert gas, as shown in FIG. 5, by arranging the downstream opening end of the exhaust gas introduction tube on the downstream side, even in the case of exhaust gas with a lot of inert gas, It can be seen that since an appropriate tubular flame can be formed in a wide range, the harmful components diluted with an inert gas can be reliably treated.

Experimental example 3
Scale-up was performed with the combustion abatement apparatus having the apparatus configuration shown in FIG. 1, and the combustion range and decomposition performance were confirmed. FIG. 7 shows the combustion characteristics with respect to the supply amount of propane gas as the fuel, and FIG. 8 shows the decomposition performance of NF ₃ . From this result, it can be seen that the scale-up is sufficiently possible.

  DESCRIPTION OF SYMBOLS 10 ... Exhaust gas introduction pipe, 11 ... 1st process cylinder, 12 ... Flame ejection hole, 12a ... Upstream end, 13 ... Exhaust gas introduction cylinder, 13a ... Downstream opening end, 21 ... 2nd process cylinder, 22 ... Oxygen containing gas Ejection hole, 22a ... upstream end, 23 ... combustion gas introduction cylinder, 23a ... downstream opening end, 31 ... third treatment cylinder, 32 ... inner cylinder, 33 ... outer cylinder, 34 ... air introduction chamber, 35 ... air introduction 36, air ejection hole, 41 ... protective cylinder

Claims (5)

In a combustion abatement apparatus for detoxifying harmful components contained in exhaust gas in a combustion flame, an exhaust gas introduction pipe having an inner diameter D0 and a first treatment cylinder having an inner diameter D1 provided downstream of the exhaust gas introduction pipe When a second processing tube having an inner diameter which is provided downstream of the first treatment column is D2, an inner diameter which is provided on the downstream side of the second processing barrel and a third treatment column of D3, the first The one processing cylinder includes a flame injection hole having a circumferential width W1 for injecting a combustion flame in a tangential direction from the peripheral wall of the first processing cylinder, and the second processing cylinder supplies an oxygen-containing gas to the second processing cylinder. A combustion abatement apparatus comprising oxygen-containing gas ejection holes having a circumferential width W2 ejected from a circumferential wall in a tangential direction, wherein the inner diameter D1 is larger than D0 + 2W1, and the inner diameter D2 is larger than D1 + 2W2 . The third processing cylinder is formed in a double structure of an inner cylinder having an inner diameter D3 and an outer cylinder covering the outer periphery of the inner cylinder, and the outer cylinder is formed between the outer cylinder and the inner cylinder. The inner cylinder includes an air introduction portion that introduces air into the air introduction chamber, and the inner cylinder includes a plurality of air ejection holes for ejecting the air introduced into the air introduction chamber into the inner cylinder. The combustion abatement apparatus according to claim 1, wherein the combustion abatement apparatus is set to be equal to or larger than the inner diameter D2. The exhaust gas introduction pipe has an axis that coincides with the axis of the first processing cylinder, and the downstream opening end of the exhaust gas introduction pipe is at the same position as the upstream end of the flame ejection hole in the first processing cylinder or the flame ejection hole. The combustion abatement apparatus according to claim 1, wherein the combustion abatement apparatus protrudes downstream from the upstream end of.   A cylindrical shape having an axis that coincides with the axis of the first processing cylinder and the second processing cylinder between the first processing cylinder and the second processing cylinder and having an outer diameter smaller than the inner diameter of the second processing cylinder. The combustion gas introduction cylinder is provided, and the downstream opening end of the combustion gas introduction cylinder is located at the same position as the upstream end of the oxygen-containing gas ejection hole in the second processing cylinder or from the upstream end of the oxygen-containing gas ejection hole. The combustion abatement apparatus according to any one of claims 1 to 3, which protrudes downstream.   The combustion abatement apparatus according to any one of claims 1 to 4, wherein the exhaust gas introduced into the combustion abatement apparatus is diluted with an inert gas in order to reduce a harmful component concentration.

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